- streaming?
- datatypes
  - redacted
  - lang.Marker - class name, handle `type[Foo]`
  - pathlib.Path
  - decimal.Decimal
  - datetime.date, datetime.time
  - ipaddress
  - re.pattern
  - numpy types
- jackson switches
  - accept_case_insensitive_enums
  - accept_case_insensitive_properties
  - accept_case_insensitive_values
  - allow_coercion_of_scalars
  - use_base_type_as_default_impl
- codegen
- context-local switches
  - mutable_collections
- simple lite interop like inj - alt ObjMarshalerManager impl for Context
- bidirectional dc field embedding (currently unmarshal only)
- default options in config
- xml
- TaggedJson
- ta.AnyStr

See:
- https://github.com/python-attrs/cattrs
- https://github.com/jcrist/msgspec
- https://github.com/Fatal1ty/mashumaro
- https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/serializers.md#custom-serializers
- https://github.com/yukinarit/pyserde
- https://github.com/FasterXML/jackson
